Investigations into the design and development of novel screenprinted electrochemical biosensors for sugars

The aim of the studies described in this thesis was to develop a set of single shot biosensors, for low concentration measures (less the 1 mM) of glucose, sucrose and fructose. In addition, the development of a user friendly potentiostat instrumental system to display and save the data acquired, via the use of an android tablet. Chapter one describes an introduction and background to screen printed biosensors. Including the electrochemical techniques used and a basic explanation of screen printing. A brief discussion of the sugars, that will be measured in this thesis. Chapter two describes the development of a simple, low cost chronoamperometric assay, for the measurement of fructose, using a graphite-nanoparticle modified screen-printed electrode (SPCE-G-COOH). Cyclic voltammetry showed that the response of the SPCE-G-COOH enhanced the sensitivity and precision, towards the enzymatically generated ferrocyanide species, over a plain SPCE; therefore the former was employed in subsequent studies. Calibration studies were carried out using chronoamperometry and tested using a commercial fruit juice. Chapter three continues from chapter two, using studies to explore the conversion of the fructose bioassay into a fructose biosensor. More analysis of the interference of ascorbic acid (vitamin C) and a method of removing the interference signals via linear subtraction, using a secondary base electrode. Chapter four explains measuring glucose, using a unique mediator, and measuring the amperometric signal, in the reduction phase. The chapter describes the use of multiple enzymes and the optimisation of them. This section then demonstrates the modification of the glucose biosensor to a sucrose biosensor. This was achieved by the inclusion of an invertase enzyme. The studies of the glucose and sucrose biosensor were then compared against a commercially available system. Chapter five investigates a possible potentiostat system, linked to an android based tablet. The intention was to produce a simple and user-friendly system to measure and record the concentrations found. Chapter six comprises future work to be carried out and ideas. These suggestions are to improve the system allowing it to be more user-friendly and to remove some of the human errors that could be introduced into the system

Partnership in Pensions? Responses to the Pensions Green Paper

The government's pensions Green Paper 'a new contract for welfare: partnership in pensions' proposes fundamental changes to the UK's retirement income system. Members of CASE and the Department of Social Policy at LSE have looked at the likely implications of the reforms for pensioner poverty, income security in old age, economic growth, the National Insurance system, tax reliefs, and women. Agulnik's analysis of redistributive effects of the State Second Pension (SSP) shows that it will result in much better benefits for low earners than would have been the case under SERPS. However, financing this improved provision through National Insurance contributions will mean that the burden of paying for the new scheme will be heaviest for those close to the upper earnings limit. Barr questions the macro-economic advantages of increasing the amount of funded pension provision via Stakeholder pensions. He finds there is no particular reason to favour the proposed balance of 60% private pension provision to 40% public provision over some other ratio. He also finds that Stakeholder pensions will not offer contributors complete income security in retirement due to uncertainties about investment returns, annuity rates and future inflation. Falkingham and Rake argue that the Government's proposals have failed to incorporate fully the needs of women. Women will be underrepresented amongst Stakeholder pensioners, and the exclusion of very low earners and carers with children over 5 from eligibility for the SSP will adversely affect women. Agulnik then looks at the proposed tax relief rules for Stakeholder pensions. While there are good reasons for the proposed £3,600 limit to tax relief on contributions, the retention of the existing rules for personal and occupational schemes is anomalous.new contract for welfare, partnership in pensions, UK retirement income system

Randomisation before consent : avoiding delay to time-critical intervention and ensuring informed consent

Peer reviewedPostprin

Development of a simple, low cost chronoamperometric assay for fructose based on a commercial graphite-nanoparticle modified screen-printed carbon electrode

© 2017 Elsevier Ltd This paper describes the development of a simple, low cost chronoamperometric assay, for the measurement of fructose, using a graphite-nanoparticle modified screen-printed electrode (SPCE-G-COOH). Cyclic voltammetry showed that the response of the SPCE-G-COOH enhanced the sensitivity and precision, towards the enzymatically generated ferrocyanide species, over a plain SPCE; therefore the former was employed in subsequent studies. Calibration studies were carried out using chronoamperometry with a 40 µl mixture containing fructose, mediator and FDH, deposited onto the SPCE-G-COOH. The response was linear from 0.1 mM to 1.0 mM. A commercial fruit juice sample was analysed using the developed assay and the fructose concentration was calculated to be 477 mM with a precision of 3.03% (n = 5). Following fortification (477 mM fructose) the mean recovery was found to be 97.12% with a coefficient of variation of 6.42% (n = 5); consequently, the method holds promise for the analysis of commercial fruit juices

The identification of Late Holocene bog bursts at Littleton bog, Ireland: ecohydrological changes display complex climatic and non-climatic drivers

In order to clearly understand the response of raised mires to past climate change, it is important to consider the full range of drivers and responses of these ecohydrological archives. To this end, a high resolution ecohydrological record from Littleton bog, Co. Tipperary, Ireland, was generated utilizing a combination of plant macrofossils, testate amoebae, and humification analysis. Chronological control for this record was provided by a Bayesian age-depth model based on AMS radiocarbon dates. Testate amoebae-derived reconstructed peatland water tables indicate a series of sudden shifts to dry bog surface conditions at c.3140, c.2510, and c.1540 cal BP. These events display a distinctive palaeoecological signal and chronological tempo that is best explained as a result of a series of bog burst events, and which seem inconsistent with other explanations. The chronological correspondence between the bog bursts at Littleton and a set of similar events at Derryville bog, c.5km to the north, is noted, as is the broad correspondence of these events with wet-shifts indicated in regional peatland water table compilations from Britain and Ireland. A range of possible driving mechanisms for these events is proposed, including anthropogenic disturbance of the bog surface, non-linear response to climate forcing, internal bog dynamics, vegetation succession, or a combination of factors. We illustrate the need for further multi-proxy investigations to fully understand these phenomena

The Potential Value of Near Patient Platelet Function Testing in PCI: Randomised Comparison of 600 mg versus 900 mg Clopidogrel Loading Doses

Whilst poor response to clopidogrel is associated with adverse outcomes uncertainty exists as to how (a) response should be assessed and (b) poor responders managed. We utilised VerifyNow P2Y12 and short Thrombelastography (TEG) to assess 900 mg doses in (i) initial poor responders to 600 mg and (ii) in a randomised comparison with 600 mg. Blood was taken before and six hours post clopidogrel in (i) 30 volunteers receiving 600 mg (poor responders received 900 mg > two weeks later) and (ii) 60 patients randomized 1 : 1 to 600 mg or 900 mg doses. Poor response was defined as TEG %Clotting Inhibition (%CIn) or VerifyNow Platelet Response Unit (PRU) reduction <30%. (i) Poor responders to 600 mg had greater PRU reduction (45.0 versus 20.1%, P = 0.03) and greater %CIn (22.9 versus −15.1%, P = 0.01) after 900 mg but (ii) there were no significant differences between the patient groups. Near-patient assessment of response to clopidogrel is feasible and clinically useful. Whilst ineffective on a population basis 900 mg doses increase the effect of clopidogrel in initial poor responders

Evidence for a divergence in function between two glucocorticoid receptors from a basal teleost

Background: Duplicated glucocorticoid receptors (GR) are present in most teleost fish. The evolutionary advantage of retaining two GRs is unclear, as no subtype specific functional traits or physiological roles have been defined. To identify factors driving the retention of duplicate GRs in teleosts, the current study examined GRs in representatives of two basal ray-finned fish taxa that emerged either side of the teleost lineage whole genome duplication event (WGD) event, the acipenseriform, Acipenser ruthenus, (pre-WGD) and the osteoglossimorph, Pantodon buchholzi, (post-WGD). Results: The study identified a single GR in A. ruthenus (ArGR) and two GRs in P. buchholzi (PbGR1 and PbGR2). Phylogenetic analyses showed that ArGR formed a distinct branch separate from the teleosts GRs. The teleost GR lineage was subdivded into two sublineages, each of which contained one of the two P. buchholzi GRs. ArGR, PbGR1 and PbGR2 all possess the unique 9 amino acid insert between the zinc-fingers of the DNA-binding domain that is present in one of the teleost GR lineages (GR1), but not the other (GR2). A splice variant of PbGR2 produces an isoform that lacked these 9 amino acids (PbGR2b). Cortisol stimulated transactivation activity of ArGR, PbGR2b and PbGR1 in vitro; with PbGR2b and PbGR1, the glucocorticoid 11-deoxycortisol was a more potent agonist than cortisol. The hormone sensitivity of PbGR2b and PbGR1 differed in the transactivation assay, with PbGR2b having lower EC50 values and greater fold induction. Conclusions: The difference in transactivation activity sensitivity between duplicated GRs of P. buchholzi suggests potential functional differences between the paralogs emerged early in the teleost lineage. Given the pleiotropic nature of GR function in vertebrates, this finding is in accordance with the hypothesis that duplicated GRs were potentially retained through subfunctionalisation followed by gene sharing. A 9 amino acid insert in the DNA-binding domain emerged in basal ray-finned fish GRs. However, the presence of a PbGR2 splice variant that lacks this insert, as well as the loss of the exon encoding these amino acids in the genes encoding for other teleost GR2 suggests the selection of two receptors with different DNA-binding domain structures in teleosts

Carbon and metal(loid)s in parkland and road verge surface soils in the city of Liverpool, UK

Urban soils are at the interface between land and people and provide a wide variety of important ecosystem services to highly populous areas. The aims of this soil survey were (1) to measure the bulk density, carbon (C) storage and pH of surface soils (0-15 cm depth) from public spaces (parks and road verges) in the city of Liverpool, UK, and (2) to determine the likely impact of these master variables on heavy metal concentrations (As, Cd, Cu, Pb and Zn). The bulk densities and organic matter contents varied considerably in the predominantly sandy textured soils within the city boundary, resulting in diverse C densities from 1-10 kg C m2. Organic carbon formed the majority of the labile, water-soluble and extractable C pool in these soils, a fact not easily elucidated from their organic matter or C content alone. The copper and lead concentrations in the sampled soils were correlated with organic matter and organic carbon in water-extracts. Cadmium and zinc appeared to be dependent only on soil pH, whilst arsenic was related positively to organic matter, but negatively to pH. Interrelationships, and hence synonymous distributions, of all metal(loid)s existed, but were strongest between Cu and As, and Cu and Pb. These results suggest that the diverse bulk densities, and hence carbon storage, of the urban soils surveyed influenced the dispersal of metals and arseni